Chilton::ACL::Contents ATLAS I COMPUTER PROGRAMMING MANUAL

CHAPTER 1 AUTOMATIC DIGITAL COMPUTERS
- 1.1 Introduction
- 1.2 Electronic Computers
  - 1.2.1 Digital Computers
- 1.3 Addresses
- 1.4 Instruction Code
- 1.5 Jump Instructions
  - 1.5.1 Looping
  - 1.5.2 Modification Binary Numbers
- 1.6 Binary Numbers
  - 1.6.1 Negative Numbers
CHAPTER 2 THE ATLAS 1 COMPUTER
- 2.1 A General Description of Atlas 1
  - 2.1.1 The Control Unit
  - 2.1.2 The Arithmetic Units
  - 2.1.3 The Supervisor
  - 2.1.4 Storage
  - 2.1.5 Input and Output
- 2.2 The Main Store
- 2.3 Storage of information in Atlas 1
- 2.4 Instructions in the machine
- 2.5 The written form of Instructions
- 2.6 The full range of Atlas 1 addresses
CHAPTER 3 THE ACCUMULATOR
- 3.1 Floating-point numbers
- 3.2 The Accumulator
- 3.3 Standardised numbers
- 3.4 Fixed-point numbers
- 3.5 Rounding
- 3.6 Floating-point operations
- 3.7 Standardising and Rounding accumulator instructions
- 3.8 The timing of instructions
- 3.9 Some fixed-point instructions
CHAPTER 4 THE B-REGISTERS
- 4.1 General Purpose B-registers
- 4.2 Arithmetic Operations
- 4.3 Logical Operations
- 4.4 Test Instructions
- 4.5 Special Purpose B-registers
- 4.6 Modification/Counting Instructions
- 4.7 The B-test register
- 4.8 The Shifting Instructions
- 4.9 The Odd/Even Test Instructions
- 4.10 Restrictions on the use of B81-B119
- 4.11 The B-carry digit
CHAPTER 5 ROUTINES AND DIRECTIVES
- 5.1 Routines, Subroutines and Symbolic Addresses
- 5.2 Parameters
- 5.3 Preset Parameters
- 5.4 Global Parameters
- 5.5 Optional Parameter
- 5.6 Setting Expressions
- 5.7 Separators
- 5.8 The Special Parameter *
- 5.9 The Ba and Bm Parts of an Instruction
- 5.10 Half-Words, Six-Bit Words and Characters
- 5.11 Floating-Point Numbers
- 5.12 Library Routines
- 5.13 Directives
CHAPTER 6 THE REMAINING ACCUMULATOR INSTRUCTIONS
- 6.1 Standardised Unrounded Operations
- 6.2 Unstandardised Instructions
  - 6.2.1 Storing and Loading the Accumulator
  - 6.2.2 Unstandardised Multiplication
  - 6.2.3 Division with Remainder
  - 6.2.4 Miscellaneous Test Instructions
CHAPTER 7 EXTRACODE INSTRUCTIONS
- 7.1 Introduction
  - 7.1.1 Uses of the Extracode Instructions
  - 7.1.2 A-type and B-type Extracodes
- 7.2 The Logical Interpretation of Extracode Instructions
- 7.3 Allocation of Functions
- 7.4 The Accumulator Extracodes
  - 7.4.1 The Most Used Arithmetic Functions
  - 7.4.2 Other Floating-Paint Arithmetic Functions
  - 7.4.3 Accumulator functions suitable for Fixed-Point Working
  - 7.4.4 Double-Length Arithmetic
  - 7.4.5 Arithmetic Using the Address as an Operand
  - 7.4.6 Complex Arithmetic
  - 7.4.7 Vector Arithmetic
  - 7.4.8 Half-Word Packing
- 7.5 B-register Arithmetic
  - 7.5.1 General B-register Operations
  - 7.5.2 Character Data Processing
  - 7.5.3 Logical Accumulator Instructions
- 7.6 Test Instructions
  - 7.6.1 Accumulator Test Instructions
  - 7.6.2 B-register Test Instructions
- 7.7 Subroutine Entry
- 7.8 Miscellaneous Operations
CHAPTER 8 INPUT AND OUTPUT
- 8.1 Introduction
  - 8.1.1 Peripheral Devices
  - 8.1.2 The System Input and Output Tapes
  - 8.1.3 Internal Code Input and Output
  - 8.1.4 Binary Input and Output
- 8.2 The Internal Code
  - 8.2.1 Abbreviations
  - 8.2.2 The Internal Code Table
  - 8.2.3 Shifts and Case Changes
- 8.3 Carriage Control Characters and Records
- 8.4 Selecting Input and Output
- Input using Ll00
  - 8.5.1 Line reconstruction
  - 8.5.2 Entries to L100
  - 8.5.3 Data Preparation for L100
  - 8.5.4 Punching Errors
- 8.6 The Entries to Ll00 in Detail
  - 8.6.1 A1/Ll00 (am' = floating point number)
  - 8.6.2 A2/Ll00 (b81' = 21-bit integer without octal fraction)
  - 8.6.3 A3/L100 (b81' = character)
  - 8.6.4 A4/L100 (lose current line)
  - 8.6.5 A5/L100 (input text)
  - 8.6.6 A6/Ll00 (input text)
  - 8.6.7 A7/Ll00 (b81' = 24-bit integer)
  - 8.6.8 A8/Ll00 (b81' = 21-bit integer with octal fraction)
  - 8.6.9 A9/L100 (print reconstructed line)
- 8.7 Optional Parameters of L100
  - 8.7.1 A20/L100 (private use of reconstructed line)
  - 8.7.2 A21/L100 (spurious character in place of a number)
  - 8.7.3 A22/Ll00 (spurious character within a number)
  - 8.7.4 A23/L100 (number of inputs handled at one time)
  - 8.7.5 A24/Ll00 (line length)
  - 8.7.6 A25/Ll00 tab settings)
  - 8.7.7 A26/Ll00 tab settings)
- 8.8 Fault Printing by L100
- Output using L1
  - 8.9.1 Entry Points to L1
- The Entries to L1 in Detail
  - 8.10.1 A1/L1 (print a floating point number)
  - 8.10.2 A2/L1 (print an integer)
  - 8.10.3 A3/L1 (print a character)
  - 8.10.4 A4/L1 (new line or card)
  - 8.10.5 A5/L1 (carriage control)
  - 8.10.6 A6/L1 (output text)
  - 8.10.7 A7/L1 (output text)
- 8.11 Optional Parameters of L1
  - 8.11.1 A21/L1, A22/L1 (controlling places allowed before and after the decimal point on output)
  - 8.11.2 A2.5/L1 (optional sign for floating point output)
  - 8.11.3 A26/L1 (optional sign for integer output)
  - 8.11.4 A27/L1 (printed width of exponents)
  - 8.11.5 A28/L1 and A29/L1 (printed form of exponents)
- 8.12 Input and Output by Extracode
- 8.13 Binary Input and Output
- 8.14 The Input Extracodes
- 8.15The Output Extracodes
- 8.16Further Information on Binary Input/Output
CHAPTER 9 MAGNETIC TAPE
- 9.1 Introduction
- 9.2 Atlas One Inch Tape
- 9.3 Block Transfers on One Inch Tape
  - 9.3.1 Block Transfer Instructions
  - 9.3.2 Use of Block Transfers
- 9.4 Variable Length working on One Inch Tape
  - 9.4.1 Variable Length Instructions
  - 9.4.2 Start and Select Instructions
  - 9.4.3 Transfer and Organisational Instructions
  - 9.4.4 Efficiency of Variable Length Working
- 9.5 Organisational Instructions for One Inch Tape
  - 9.5.1 Mount Instructions
  - 9.5.2 Other organisational Extracodes
- 9.6 Specification of the Atlas One Inch Tape System
  - 9.6.1 Control
  - 9.6.2 The Tape Layout
  - 9.6.3 Performance
  - 9.6.4 Safeguards
- 9.7 Orion Tapes
- 9.8 Atlas Half inch Tape
- 9.9 Half Inch Tape Instructions
  - 9.9.1 The Selection Instructions
  - 9.9.2 The Transfer Instructions
  - 9.9.3 The Skip Instructions
  - 9.9.4 Other Instructions
  - 9.9.5 Summary of Half Inch Tape Instructions
- 9.10 Specification of the Atlas Half Inch Tape System
  - 9.10.1 Control
  - 9.10.2 The Tape Layout
  - 9.10.3 Performance
  - 9.10.4 Safeguards
- 9.11 Half Inoh Tape Faults
CHAPTER 10 PREPARING A COMPLETE PROGRAM
- 10.1 Atlas Jobs
- 10.2 Documents
- Document Headings and Titles
  - 10.3.1 Headings
  - 10.3.2 Titles
  - 10.3.3 Rules for title preparation
- 10.4 The Input and Output Sections of the Job Description
  - 10.4.1 The Input Section
  - 10.4.2 The Output Section
  - 10.4.3 Output: General Notes
- 10.5 A Complete Job Description
- 10.6 The Magnetic Tape Section of the Job Description
  - 10.6.1 Single Tapes
  - 10.6.2 Files
  - 10.6.3 Deck Allotment
- 10.7 Time Estimates for a Job
  - 10.7.1 Computing Time
  - 10.7.2 Execution Time
- 10.8 Store Allocation
- Job Description Format
  - 10.9.1 Order of Sections
  - 10.9.2 Case Changes
  - 10.9.3 Backspace
- 10.10 Composite Documents
  - 10.10.1 Job Description combined with Program
  - 10.10.2 Job Description combined with Data Document
  - 10.10.3 Data Files
- 10.11 Tape and Card Markers
  - 10.11.1 The Tape Markers ***Z, C, T and A
  - 10.11.2 The Binary tape Markers ***B, E and F
  - 10.11.3 The Tape Marker ***P
  - 10.11.4 Card Markers
- 10.12 Input and Output using Private Magnetic Tapes
  - 10.12.1 Extensive Output
  - 10.12.2 Job description Reference
  - 10.12.3 Re-use of Documents on System Tapes
  - 10.12.4 Extensive output
- 10.13 Job Description Parameter
CHAPTER 11 MONITORING AND FAULT DETECTION
- 11.1 Supervisor Monitoring
  - 11.1.1 Types of Program Faults
  - 11.1.2 Standard Post Mortem
  - 11.1.3 Ending a Program
- 11.2 The Trapping Vector
- 11.3 Private Monitoring
- 11.4 Restarting and Re-entering a Program
  - 11.4.1 Preventing a Restart
  - 11.4.2 Re-entering a Program
- 11.5 Monitor Extracodes
- 11.6 Faults Detected by the Compiler
  - 11.6.1 B-lines in ABL
  - 11.6.2 Indeterminate Items
  - 11.6.3 Diagnostic Printing
  - 11.6.4 Fault Location
  - 11.6.5 Diagnostic Printing Character Set
  - 11.6.6 Explanatory Texts
CHAPTER 12 FURTHER FACILITIES AND TECHNIQUES
- 12.1 Programmed Drum Transfers
- 12.2 Optimization of Program Loops
  - 12.2.1 Store Access
  - 12.2.2 The Overlapping of Instructions
- 12.3 Branching
  - 12.3.1 Existing Parallel Operations
  - 12.3.2 The Branch Instructions
  - 12.3.3 The Use of Branching
  - 12.3.4 Store Requirements
- 12.4 Instruction Counters
- 12.5 Re-entering the Compiler
- 12.6 Special Preset Parameters
- 12.7 Private Library Routines
  - 12.7.1 Library Routine Titles
  - 12.7.2 Undefined Library Routines
  - 12.7.3 Preparing a Private Library Routine
  - 12.7.4 Incorporating a new Library Routine into the Public Library
  - 12.7.5 Conventions
  - 12.7.6 Referring to the master program from within a library routine
- 12.8 Correction of Programs, and System Peculiarities
  - 12.8.1 Program Alterations
  - 12.8.2 Further Peculiarities
- 12.9 Compiler and Supervisor Extracodes
APPENDIX A References
APPENDIX B Notation
APPENDIX C V-Store addresses of Peripherals
APPENDIX D Character Codes
APPENDIX E Summary of Extracodes
APPENDIX F Summary of Basic Instructions by Function
APPENDIX G Summary of Basic Instructions by Number